OpenAnyFile
Works
Viewing, inspecting and verifying. You get a browsable listing of everything inside, decompressed in-browser by libarchive compiled to WebAssembly. File details, exact byte size and the detected signature are always shown.
How to open a .lz4 file
Opening a LZ4 file usually means tracking down special software. It does not have to. Here is what the format really is, and a browser-based way to read one right now.
What is a .lz4 file?
LZ4 Compressed File is an archive format developed by Yann Collet, first appearing in 2011. It is normally produced by Filesystems, databases, kernel images.
Optimised for speed rather than ratio — it decompresses at gigabytes per second on one core, which is why ZFS, Btrfs and several databases compress inline with it.
| Full name | LZ4 Compressed File |
|---|---|
| File category | Archives |
| MIME type | application/x-lz4 |
| Magic bytes (file signature) | 04 22 4D 18 |
| Developer | Yann Collet |
| Introduced | 2011 |
| Usually created by | Filesystems, databases, kernel images |
| OpenAnyFile engine | libarchive WASM engine |
| Opens without upload | Yes — parsed locally in your browser |
Open a .lz4 file in your browser
OpenAnyFile routes .lz4 to its libarchive WASM engine, which opens a browsable listing of everything inside, decompressed in-browser by libarchive compiled to WebAssembly.
- Open the OpenAnyFile opener in this browser — nothing to download or sign up for.
- Drag your .lz4 file onto the drop zone, click to browse for it, or paste it with Ctrl+V.
- The extension is detected and the file is handed to the libarchive WASM engine.
- Your LZ4 opens on its own viewer page: a browsable listing of everything inside, decompressed in-browser by libarchive compiled to WebAssembly.
- Use fullscreen for a closer look, or download the file back out unchanged. Nothing is transmitted anywhere — the parsing happens in your own browser process.
What you can and cannot do with it here
Does not work
Editing and re-saving. OpenAnyFile is a reader, not an editor — for changes you still need special software or an equivalent.
Why your {ext} file is never uploaded
Most online viewers work by sending your file to their server, processing it there, and leaving a copy behind on infrastructure you do not control. OpenAnyFile does not. Your .lz4 file is read through the browser's local File API and decoded by JavaScript and WebAssembly running on your own machine. There is no upload step and no server-side copy — open your browser's network tab while you do it and watch: the file never appears.
Frequently asked questions about LZ4 files
Can I open a .lz4 file without installing special software?
Yes. OpenAnyFile's libarchive WASM engine runs in your browser, so you can read a LZ4 file with nothing installed. You get a browsable listing of everything inside, decompressed in-browser by libarchive compiled to WebAssembly. For full editing you still need the original application — this is a viewer, not an editor.
How can I check a file really is a LZ4 file?
Look at the first bytes rather than the extension. A genuine LZ4 begins with 04 22 4D 18. Opening the file in OpenAnyFile shows that signature in the file-details panel, so a file renamed to .lz4 by mistake is easy to spot.
Is it safe to open a LZ4 file online?
With OpenAnyFile, yes, because nothing is uploaded. The file is read locally through your browser's File API and never leaves your device, so there is no server copy to leak, log or retain. That matters most for the kind of file people are least willing to hand to a random converter site.
What is a .lz4 file, exactly?
LZ4 Compressed File — an application/x-lz4 format created by Yann Collet since 2011. Optimised for speed rather than ratio — it decompresses at gigabytes per second on one core, which is why ZFS, Btrfs and several databases compress inline with it.
Does the same viewer handle formats related to LZ4?
Yes — the same engine also opens .7z, .iso, .rar, so you can compare related files without switching tools.
Related formats
These open with the same engine, so if you have one of these sitting next to your .lz4 file, it will open too: